Improvement in preparing paper to take copies



UNITED STATES PATENT OEEIOE.

FnEDEmoK HAWKE, OF LONDON, ENGLAND.

IMPROVEMENT IN PREPARING PAPER TO TAKE COPIES.

Specification forming part of Letters Patent No. 210,690, dated December 10, 1878; application filed October 18, 1877; patented in England, May 17, 1877.

of 10 St. J ohns Wood Park, London, in the county of Middlesex, England, have invented improvements in the preparation of paper for taking impressions of matter, written or printed, in inks which are prepared or unprepared, for copying purposes, as fully set forth herein.

This invention has for its object, in chief, to provide paper which, by the usual practice of damping before use, as with ordinary copying-papers, will readily take impressions from written or printed matter which has been produced with ink free from the impurities inseparable from specially-prepared copying-ink. I thereby render it possible and advantageous to use apurer, better, and cheaper ink for copying than can be used with ordinary copying-paper, which inlc is also suitable for all other purposes for which ink is used. I avoid the cost, trouble, and annoyance which result from the necessity of using two separate inks-that is to say, one kind for copying, and the other for ordinary purposes.

The paper prepared according to this invention also produces better impressions from prepared copyingink than any other paper at present in use, and will copy documents which have been previously copied.

The essential feature of my invention con sists in the preparation of special copyingpapers, by mixing oxalic or citric acid and the perchloride of iron with the pulp during the process of manufacture, (or sulphate of iron may be used in lieu of the perchloride.) Copying-papers thus made can be used in the same manner as ordinary copying-papersthat is, by moistcning them with water, in the usual way, before taking impressions of documents.

The proportions in which the acids and the perchloride of iron are to be employed are regulated according to the thickness of the paper required to be manufactured, as hereinafter described, to avoid any deterioration in the substance of the paper.

The proportions I prefer to employ are as followsthat is to say, for paper weighing twelve to fifteen pounds to the ream of four hundred and eighty sheets, each measuring nineteen by twenty-two inches, to the wa. ter used in manufacturing three hundred pounds weight of pulp from the rag-engine I add about one and a half gallon of perchloride of iron, calculated at Fe Gl and in which is dissolved about sixteen ounces of pure crystals of oxalic acid. For a paper weighing six to seven and a half pounds to the ream of four hundred and eighty sheets, each measuring nineteen by twen ty-two inches, to the water used in manufacturing three hundred pounds weight of pulp from the rag-engine I add about one and a quarter gallon of perchloride of iron, calculated at I e- 01 and in which is dissolved about twelve ounces ofpure crystals of oxalic acid. For other thicknesses of paper I use a corresponding strength of solution to those indicated above, according to the weight per ream.

I use the above-named combination as the cheapest and best; but other acids, such as citric, may be employed, and I may use either the perchloride or sulphate of iron. From the latter salt, however, I have not obtained such good results.

I claim as my invention- The preparation of special copying-papers by mixing oxalic or citric acid, in combination with the perchloride or sulphate or iron, with the pulp during the process of manufacture, as hereinbefore described.

FREDERICK HAVVKE.

IVitnesses:

JOHN HAWKE,

7 St. Mt'ldrcds Court, London. WILLIAM GnANvILLE HAWKE,

7 St. Mildrcds Court, London. 

